After using TsiLang Expert to scan your source code you can just combine the second line into the first one (using Ctrl+Enter or menu Edit | Multiline Editor in Translations Editor). And then delete the call for second GetTextOrDefault() method. Also performing global replace
_( to just ( would be enough to eliminate the call for _() function.

If you don't wish to remove _() call then you can leave the _() function call and let TsiLang translate the content inside of () using TsiLang Expert. Then just create new _() function, something like this:
function _(const S: string): string;
begin
Result := S;
end;
In this way you wouldn't need to make any replacement in your code for _() function.